Section 5 - Samlexpower Evolution EVO-1212F Owner's Manual

SECTION 4 |
synchronized with the AC input source. This synchronization process takes few seconds. Once
synchronization is completed, the load is transferred instantly (within 1 ms) to the AC input
source at Zero Crossing of the voltage waveform for seamless transfer and for better protection
of Transfer Relay contacts. The unit now operates in "Charging Mode". In "Charging Mode",
AC input power from the Grid / Generator is used to charge the batteries and is also passed
through to power the AC loads.
4.4.4 Synchronized Transfer From AC Input Source to Inverter
When the unit is operating in "Charging Mode" as described above, the phase and frequency
of AC input power are tracked continuously. In case AC input power fails or is disconnected, the
inverter will be forced into transfer at voltage which is at the same phase and frequency at which
the AC input power had been disconnected. Load will be transferred to the inverter within 16ms at
zero crossing. The unit will now work in "Inverting Mode" and the batteries will start discharging.
4.5 BATTERY CHARGER SECTION
The Battery Charger Section of these units provide 2/3/4 stage charging with 6 programmable
charging profiles as detailed at Table 5.2, Section 5.6. The same Isolation Transformer and the H-
Bridge configuration of the Inverter Section are used to work in the reverse direction, i.e. the AC
input is stepped down and rectified to the programmed DC battery charging voltage using Pulse
Width Modulation (PWM) Control. That is why it is called a Bi-directional device. Further, the
charging voltages and currents are programmable to take care of a wide range of battery types
like Lead Acid flooded, AGM, Gel Cell, Lead Calcium and Lithium.
Important battery charging features are as follows:
• Adaptive Charging Control
• Dynamic Input Power Diversion Control
• Parallel charging through External Charge Controller
• Temperature compensated charging
• Programmable Charging Profiles for Lead Acid and Lithium Batteries
Please see details under Section 5 titled "Battery Charging in Evolution
4.6 MODES OF OPERATION
4.6.1 Charging Mode
As long as the external AC input power from the Grid/Generator is available and is within the
programmed limits of voltage and frequency, it is passed through to the AC load through the
Transfer Relay Section. At the same time, the Battery Charger Section converts the external AC
input power from the Grid/Generator to DC power to charge the DC Battery Source.
4.6.2 Inverting Mode
If at any instant, the external AC input power from the Grid/Generator is interrupted or is not
within the programmed limits of voltage and frequency, the Transfer Relay is de-energized and
the load is transferred to the Inverter Section and internal battery charging is terminated. This is
called the Inverting Mode.
4.6.3 Power Saving Mode
When the unit is operating without any load connected to it, it requires some minimum input
power from the battery to keep all the sections inside the unit alive and ready to deliver power to
the AC load as soon as the load is switched on. This power is called the "No Load Power Draw" or
the "Idle Power" or "Self Power Consumption". The "No Load Power Draw" of these units in the
General Description & Principles of Operations
Series".
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